Liquid Cooled Cherokee 180 sails by a Piper Arrow IV

Powered by a Cool Jugs, liquid cooled Lycoming O-360 engine.

12/16/03

When it comes to proving how fast an airplane can go nothing beats an air-to-air comparison. We suspected that our Cool Jugs Cherokee 180 was flying quite a bit faster than it did with its standard aircooled engine but we wanted to be sure. So we set out to compare our fixed gear, hershey bar winged, liquid cooled Cherokee 180 against a 1979 Piper PA28RT-200, Arrow IV - a retractable gear, 200HP airplane with a more efficient semi tapered wing. What we witnessed surprised even us.

Of course this would all be just 'hangar talk' without proof so before taking to the air we brought our trusty video camera along on the Arrow IV so we could record the results of our test. As you will see - the video camera wasn't operated by a professional and its a little rough - a testament to the fact that nothing was rehearsed. Watch the video. You will notice the somewhat less than perfect formation flying but in the end you will watch our liquid cooled Cherokee 180 just walk on by the Piper Arrow IV.

At Liquid Cooled Air Power, we set out almost 8 years ago to create a liquid cooled aircraft piston engine that could be used in both new and existing aircraft. We knew that liquid cooling the engine would bring greater reliability, performance and fuel economy. We also suspected that existing aircraft would achieve some performance gains based on the reduction in cooling drag that is possible with a liquid cooled engine installation along with some drag reduction due to more streamlined cowling designs. However, we didn't expect to achieve such a substantial performance gain on an existing arircraft with so little effort.

The only real difference between the stock Cherokee 180 and our Cool Jugs conversion is firewall forward. We have not modified any other part of the airframe as part of the conversion. The significant modifications are the Cool Jugs liquid cooling conversion, the re-designed cowling and an MT 3 bladed electric constant speed propeller. We know from dyno data that the engine in the Cherokee 180 is putting out 185 hp at most. Furthermore, the extra blade of 3 bladed propeller creates additional propulsion drag when compared to a 2 bladed propeller. The Piper Arrow IV is a completely stock airplane with a 2 bladed constant speed propeller. In effect the Arrow IV has all of the advantages - retractable gear, a semi tapered wing, 20HP more, a 2 bladed propeller. Yet we still went past it. The pilot of the Arrow IV could barely believe what he was seeing.

Here is a look at the Arrow IV from the Cherokee:

While others are just talking about new engines - we are flying one. We are proving the value and performance of a liquid cooled engine in flight, in an existing aircraft, using a well known base engine that is purpose designed for powering aircraft and that is well supported in the field today!

Aircooled engines are obsolete - they just don't know it yet...